The present invention is related to machines used in the repair of railroad tracks, and more specifically to machines which drive spikes into railroad ties. An apparatus is provided for fixing the position of a spike driver gun over a desired location for spike placement.
Conventional spike driving machines comprise a motorized, wheeled frame to which is mounted at least one, and preferably two or four hydraulically powered spiker guns, one gun for each side of a rail. With four guns, both rails may be repaired simultaneously. Spiker guns basically comprise a hydraulic ram with a flat-ended shaft as the contact point. Problems occur when the flat end of the shaft contacts the rounded head of a spike.
Often, improper spike positioning, or discontinuities in spike shape or tie composition cause the ram to be deflected off of the spike head, most often in a direction perpendicular to the rail. This deflection results in bent spikes, the removal of which is quite time consuming. Further, the spiking operation must progress at a fairly rapid rate due to the large number of ties per mile (on the order of 3,000) and the generally repetitive nature of the work.
One previous attempt to solve this problem involved the use of a turn buckle to connect the spiker gun to the frame and ensure gun stability during the spike driving process. Unfortunately, this method required excessive manual adjustments to properly position the gun for each spike placement. Another attempted solution involved the use of a rigid gusset extending from the frame to the spiker gun to provide lateral support. This proved to be unsatisfactory due to the lack of adjustability.
A third alternative involved the mounting of a hydraulic strut between the frame and the spiker gun. However, the hydraulic cylinder was unable to maintain constant locking pressure due to fluid seepage.
Thus, there remains an outstanding need for a means of adjustably locking the position of a spiker gun to prevent movement perpendicular to the rail during the spike driving operation, while still permitting the freedom of movement necessary to position the gun over spike holes in various locations.
It is therefore an object of the present invention to provide a spiker gun locking strut which is capable of fixing the position of the gun over the spike, while having the ability to adjust the gun's position over different spike holes and in response to discontinuities in track construction.